How much electrical power does your business site have?

Check your connection agreement, then compare its capacity with measured site demand and an electrical survey. National Grid identifies the supply on your bill using a 13-digit MPAN [S1]. A fuse label or annual electricity total cannot establish spare charging capacity. Ask your network operator to confirm the connection before choosing equipment. Checked October 2026.

Last checked 16 October 2026

How do you find out how much power your site has?

Start with the paperwork for the actual electricity connection serving your proposed chargers. Find a recent bill, the connection agreement and any previous capacity-change offer. Match the site address and supply identifier before using a figure from an old landlord pack. National Grid says agreed maximum import capacity can appear in the connection agreement and may also appear in the supply contract. [S1] Use the capacity charges guide to prepare questions about the recurring bill.

Maximum import capacity is the amount your site is allowed to draw from the network. It is expressed in kilovolt-amperes, or kVA. UK Power Networks describes it as the maximum power a property can draw at a given time. That is different from how much energy you bought across a billing period. [S4]

Kilowatts (kW) describe power; kilowatt-hours (kWh) describe energy delivered over time. For an illustration, not a design calculation, a steady 10 kW load running for 3 hours uses 30 kWh: 10 × 3. Your designer must put supply capacity and equipment demand on a consistent basis before subtracting them. Read the kW and kWh explanation before comparing charger proposals.

What connection size do your chargers need?

Begin with what vehicles need before departure. Government guidance asks how many chargepoints you need and how quickly vehicles must charge. It also recommends reviewing existing site electricity use before paying for more capacity. [S3] A charger shopping list is therefore an output of the exercise, rather than the starting point.

Ask your electrical designer to complete this evidence table. It separates the permission to import power from the physical installation and the demand already using it. UK Power Networks’ pre-application service can investigate the existing service and fuse arrangement when those records are unclear. [S2]

Do not treat the fuse marking as permission to import that amount continuously. Ask for confirmation of both the agreed limit and the assessed physical capability. Keep photographs for the professional assessing the installation; leave sealed equipment and live electrical compartments to authorised people. [S1] [S2]

How can you check spare capacity without buying a grid upgrade?

Request interval consumption data from your electricity supplier and ask the designer whether additional monitoring is needed. Include busy trading periods and the machinery, heating or refrigeration that matters at your site. Government guidance specifically suggests changing when machinery runs to free capacity for charging. [S3]

The useful question is what remains during the charging window. An annual bill can describe total consumption but cannot show whether your kitchen and chargers compete at lunchtime. Equally, a quiet overnight period is only useful if vehicles are actually connected then. Compare a pub’s customer charging window with a depot’s departure plan before transferring assumptions from one site to another.

Here is an illustration, not a quote or electrical approval. Assume the designer establishes an operational ceiling of 100 kW on a consistent basis. Existing demand is 75 kW during trading and 30 kW overnight. Arithmetic headroom is 25 kW during trading and 70 kW overnight: 100 minus the existing load. The designer still needs to allow for the actual installation, changing demand and any operating restrictions.

If the illustrative vehicles need 200 kWh over 8 hours, their average delivered power requirement is 25 kW: 200 ÷ 8. This is before charging losses and scheduling constraints. A nameplate total above that does not prove an upgrade is needed; nor does the average establish that every departure will be met. Compare load management with an upgrade using the actual timetable.

Do you need to contact your distribution network operator?

A distribution network operator (DNO) manages your local electricity network. Government guidance recommends early discussion for workplaces and depots installing multiple chargers. For smaller installations, the installer should assess whether the network operator needs notification before or after installation. Follow that assessment rather than assuming an existing electricity supply removes the need to involve the network. [S3]

Your next request should be specific: confirm the existing capacity, assess the proposed controlled charging load and identify whether a capacity change is required. Include the site address, supply identifier, current capacity, proposed capacity and contact details. Those are among the information items National Grid requests for a load amendment. [S1] Ask the installer to keep the application consistent with the system being quoted.

Treat a network map as a conversation starter. It cannot replace checking your own service. UK Power Networks separately offers network datasets and an assessment of your existing connection. [S2] Review the grid upgrade cost guide once the missing work has been identified.

What should you do next?

Bring your bill, connection agreement, demand data, parking plan and vehicle timetable to the enquiry. Note whether you own the land and which decisions need landlord approval. Use the site survey guide to organise the questions that remain open.

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